Description GtkGLExt is an extension to GTK which adds OpenGL capabilities to GtkWidget. Its use is quite simple: use gtk_widget_set_gl_capability to add OpenGL support to a widget, it will create a OpenGL drawable (GdkGLDrawable) for the widget, which can be obtained via gtk_widget_get_gl_drawable. OpenGL rendering context (GdkGLContext) can also be obtained via gtk_widget_get_gl_context. With GdkGLDrawable and GdkGLContext, gdk_gl_drawable_gl_begin and gdk_gl_drawable_gl_end can be called, and OpenGL function calls can be made between those two functions.